Run Heroku Rails apps in production mode locally
https://www.lukeko.com/11/run-heroku-rails-apps-in-production-mode-locally 0Procfile
web: bundle exec puma -t 5:5 -p ${PORT:-3000} -e ${RACK_ENV:-development}
.env
RACK_ENV=production
PORT=3000
.gitigore
.env
% rails assets:precompile
% heroku local